One of the background arts in the present technical field is that disclosed in Japanese Patent Laid-open No. 2011-124503 (Patent Literature 1). This document describes that an electromagnetic noise in a high frequency band is suppressed from being radiated from a space between the back of a wiring board and the internal surface of a housing.
Japanese Patent Laid-Open No. 2014-27180 (Patent Literature 2) describes that a circuit board which makes it possible to achieve both size reduction and suppression of malfunctions due to mutual interference between elements, noise, or the like is provided.